Friday Q&A: How to Stretch?

Q: How long should I hold a stretch for maximum benefits?A: Before I answer this reader’s question, I’d like to give provide background on flexibility and stretching in general. To start, I’d like to clarify exactly what I mean by “flexibility.” One accepted definition that I like is: Flexibility is defined as the ability to move through a specific joint range of motion (ROM)An example of good elbow joint flexibility would be having an elbow that folds to about a 25-degree angle and that opens to about a 180-degree angle. If you discovered that your elbow only opened to about 150 degrees, which could definitely limit some of your daily activities, you might want to increase your flexibility at that joint. Can stretching of the sort we do in yoga eventually improve your range of motion at the elbow? I’ll get that in a moment. But let's start by looking at stretching in general.How does Stretching improve Flexibility?Research has demonstrated that stretching can increase the range of motion of joints, but how does it do it? Is there some mechanism responsible, such as a mechanical change in the muscles, to account for the improved flexibility or is there some other explanation? It turns out there are two theories about how stretching works, one that indeed proposes that there is some mechanical change in the structure and function of the actual muscles and another that proposes that there a neurological change in the sensation associated with stretching. I came across this informative review article on just this topic Does stretching really change muscle length? that proved quite interesting and helpful in my own understanding. I recommend that you read it if you want to get into the nuts and bolts of all the research these folks reviewed to come to some helpful conclusions about stretching.A review of quite a few studies on mechanical explanations for stretching’s effects on flexibility, such as viscoelastic deformation, plastic deformation, increased sarcomeres in series, and neuromuscular relaxation of the stretch reflex failed to prove any of the theories out there in this particular camp. On the other hand, the other explanation for how stretching leads to improved flexibility, sometimes referred to as the “sensation theory,” shows that the only variable that changes following stretching programs in tandem with flexibility is the sensation of pain (that is, maximum pain and onset of pain) during the stretch. This has lead to the formation of a hypothesis that stretching increases flexibility by reducing the sensation of increasing muscle length. “Stretch tolerance,” as this is referred to, seems to develop over a 3-8 week period of regular stretching, and does lead to significant improvements in flexibility. Yoga Asana Ways of StretchingThere are two main styles of stretching that yoga asana employ: dynamic and static. And non-yoga studies on stretching to improve flexibility hamstrings, calves and ankles have shown stretching improved flexibility in those areas. Not so impressive is the finding that the effects of short-term stretching don’t last much longer than one day or so. Beyond a day or two, muscles return to pre-stretch length if you don’t stretch regularly—perhaps good motivation to have a regular home practice!If you are doing yoga stretches to improve your performance in other activities, such as running or some other sport, studies have shown that static, held stretches greater than 45 seconds can actually reduce performance acutely right after stretching, at least for a while after stretching. On the other hand, dynamic stretching seems to have no negative, and maybe slightly positive impacts acutely on sports performance. So I’d recommend that you don’t do long static yoga stretches right before you head out for an hour of cycling or a long stint at the rock climbing gym. Save the static stretches for afterwards or put a day in between a good yoga practice and your other favorite physical activity. On the other hand, if your goal is to go further into more challenging poses that require better flexibility, I find dynamic stretches do lead to immediate improvements in muscle flexibility that I can then further with my static hold of the same pose. For example, moving dynamically in and out of Standing Forward Bend (Uttanasana) with my breath leads to improved hamstring/hip flexibility, which I can then further with a long hold of the pose. Quite interestingly, long-term stretching regimens have actually been shown to improve performance in physical activities over time, as well as improving overall strength as well. How unexpected and fascinating that regular stretching can lead to improved strength! Passive and active stretching is thought to lead to muscle hypertrophy (growth), although the mechanisms are complex and incompletely understood. The results, however, are welcome: stretching not only improves flexibility but improves strength over time! If you want to know more about it, see Stretching is Really a Form of Strengthening for details.Does Stretching Reduce Injuries?Studies of non-yoga stretching unfortunately have not shown that regular stretching reduces other sports injuries. But, those studies have not shown an increase in injury rates, either. So, at this time, we should not claim that regular stretching, yogic or otherwise, reduces your risk of injuries, such as ankle sprains when you go for a long hike. How Long to Stretch?Finally, getting back to our original question, how long should you stretch for maximum benefit? There is some recent research that shows the protein titin, which is found in muscles, changes shape and may contribute to a stretch lasting for several days when a stretch is held for longer periods of time, say 90 seconds (see Yoga and Flexibility: An Overview). So I personally recommend a combination of small dynamic sequences of stretches done for 6-8 repetitions, followed by holding the stretch statically for 90 seconds. For example, when I am trying to stretch the psoas and rectus femoris (of the quads), I often practice moving dynamically from Extended Childs pose to Cobra pose and back for 6-8 rounds, followed by holding Cobra pose for 60-90 seconds. In general, with consistent practice, you can see results after at least 3 to 8 weeks. As for how often and when you stretch, that depends on your goals. (See Tension versus Compression and How Much Stretch is Enough for information about how far to stretch.)

If you are taking up yoga to improve your flexibility and strength for a sport, such as running or rock climbing, which take advantage of both flexibility and strength, then do your yoga stretches, dynamic and static, on days other than your sport days. On your sport days, you could do dynamic stretches before the sports activity since they don’t negatively impact performance, but skip the held stretches.

If you are taking up yoga to simply combat the stiffening and tightening of your body from years of sitting at work, you can do your stretches anytime you want. As I always recommend, start out with a shorter daily home practice that you can do reasonably and gradually add more time and challenge to your stretches as you advance. If you stretch a particular muscle or muscle group regularly, probably do it no more than every other day (we don’t want to overdo it and cause overuse injuries!).

If you are doing yoga asana regularly and your goal is to master more challenging poses, you will want to be consistent in stretching over several weeks to look for noticeable changes in flexibility. To give your body time to rest and repair, you will want to alternate intense stretching days with other types of yoga practice, whether that is an active, challenging practice, a gentle or restorative practice, or pranayama/meditative practice on your “off days.”

Although I have tried to go in great detail here about what we know about stretching, I have no doubt there will be more to share in the future. So, until then, happy stretching!—BaxterSubscribe to Yoga for Healthy Aging by Email ° Follow Yoga for Healthy Aging on Facebook ° Join this site with Google Friend Connect